Stack serves as a collection of elements. There are two main operations of Stack.
Push - Adds elements to the collection.
Pop - Removes elements from the collection.
Stack works in a LIFO (Last in, First Out) manner. It is considered a linear data structure. The push and pop operations occur only at one end of the structure.
Stack Class in C#
We have Stack class in C#. It represents a simple last-in-first-out (LIFO) non-generic collection of objects.
Namespace:
System.Collections
Assemblies
System.Collections.NonGeneric.dll, mscorlib.dll, netstandard.dll.
Stack<T> Class (Generic Version)
Namespace:
System.Collections.Generic
Assemblies:
System.Collections.dll, System.dll, netstandard.dll
Example- Reverse a string using Stack
Code
  1. using System;
  2. using System.Collections.Generic;
  4. namespace ReverseAStringUsingStack
  5. {
  6. class Program
  7. {
  8. static void Main(string[] args)
  9. {
  10. Console.WriteLine("Enter a String:");
  11. string sInput = Console.ReadLine();
  12. string sOutput = ReverseAString(sInput);
  14. Console.WriteLine("\n Reversed String is: " + sOutput);
  15. Console.Read();
  16. }
  18. private static string ReverseAString(string sInput)
  19. {
  20. Stack<char> objStack = new Stack<char>();
  21. string sOutPut = string.Empty;
  22. if (sInput != null)
  23. {
  24. int iInputLength = sInput.Length;
  26. for (int i=0;i<iInputLength;i++)
  27. {
  28. objStack.Push(sInput[i]);
  29. }
  31. while (objStack.Count != 0)
  32. {
  33. sOutPut += objStack.Pop();
  34. }
  35. }
  36. return sOutPut;
  37. }
  38. }
  39. }
Output